This invention relates to the field of guide wires for advancing intraluminal devices such as stent delivery catheters, balloon dilatation catheters, atherectomy catheters and the like within a patient's body, such as within a patient's vasculature.
In a typical percutaneous procedure in a patient's coronary system, a guiding catheter having a preformed distal tip is percutaneously introduced into a patient's peripheral artery, e.g., femoral, radial or brachial artery, by means of a conventional Seldinger technique and advanced therein until the distal tip of the guiding catheter is seated in the ostium of a desired coronary artery. There are two basic techniques for advancing a guide wire into the desired location within the patient's coronary anatomy, the first is a preload technique which is used primarily for over-the-wire (OTW) devices, and the second is the bare wire technique which is used primarily for rail type systems.
With the preload technique, a guide wire is positioned within an inner lumen of an OTW device such as a dilatation catheter or stent delivery catheter with the distal tip of the guide wire just proximal to the distal tip of the catheter and then both are advanced through the guiding catheter to the distal end thereof. The guide wire is first advanced out of the distal end of the guiding catheter into the patient's coronary vasculature until the distal end of the guide wire crosses the arterial location where the interventional procedure is to be performed, e.g., a lesion to be dilated or a dilated region where a stent is to be deployed.
The catheter, which is slidably mounted onto the guide wire, is advanced out of the guiding catheter into the patient's coronary anatomy over the previously introduced guide wire until the operative portion of the intravascular device, e.g., the balloon of a dilatation or a stent delivery catheter, is positioned across the arterial location. Once the catheter is in position with the operative means located within the desired arterial location, the interventional procedure is performed. The catheter can then be removed from the patient over the guide wire. Usually, the guide wire is left in place for a period of time after the procedure is completed to ensure re-access to the arterial location if it is necessary. For example, in the event of arterial blockage due to dissected lining collapse, a rapid exchange type perfusion balloon catheter such as described and claimed in U.S. Pat. No. 5,516,336 (McInnes et al.), can be advanced over the in-place guide wire so that the balloon can be inflated to open up the arterial passageway and allow blood to perfuse through the distal section of the catheter to a distal location until the dissection is reattached to the arterial wall by natural healing.
With the bare wire technique, the guide wire is first advanced by itself through the guiding catheter until the distal tip of the guide wire extends beyond the arterial location where the procedure is to be performed. Then a rail type catheter, such as described in U.S. Pat. No. 5,061,273 (Yock) and the previously discussed McInnes et al. which are incorporated herein by reference, is mounted onto the proximal portion of the guide wire that extends out of the proximal end of the guiding catheter outside of the patient. The catheter is advanced over the guide wire, while the position of the guide wire is fixed, until the operative means on the rail type catheter is disposed within the arterial location where the procedure is to be performed. After the procedure the intravascular device may be withdrawn from the patient over the guide wire or the guide wire advanced further within the coronary anatomy for an additional procedure.
Conventional guide wires for angioplasty, stent delivery, atherectomy and other vascular procedures usually comprise an elongated core member with one or more tapered sections near the distal end thereof and a flexible body such as a helical coil or a tubular body of polymeric material disposed about the distal portion of the core member. A shapeable member, which may be the distal extremity of the core member or a separate shaping ribbon secured to the distal extremity of the core member, extends through the flexible body and is secured to the distal end of the flexible body by soldering, brazing or welding, which forms a rounded distal tip. Torquing means are provided on the proximal end of the core member to rotate, and thereby steer, the guide wire while it is being advanced through a patient's vascular system.
Further details of guide wires, and devices associated therewith for various interventional procedures can be found in U.S. Pat. No. 4,748,986 (Morrison et al.); U.S. Pat. No. 4,538,622 (Samson et al.): U.S. Pat. No. 5,135,503 (Abrams); U.S. Pat. No. 5,341,818 (Abrams et al.); U.S. Pat. No. 5,345,945 (Hodgson, et al.); and U.S. Pat. No. 5,636,641 (Fariabi); all of which are hereby incorporated herein in their entirety by reference thereto.
One of the challenges with conventional guide wires is that the distal portion is typically made from a superelastic or pseudoelastic nickel-titanium (NiTi) alloy, and due to the highly elastic behavior, the cardiologist may have issues with creating a permanent kink or bend at the distal end since the resilience of the material returns the distal tip to a relatively straight shape.
In conventional guide wires, the very distal tip has a shaping ribbon acting as a shapeable tip that can be finger bent or kinked. The shaping ribbon or shapeable tip is usually a discrete part that is made from a different material than the superelastic NiTi distal core. This material that can be permanently deformed is welded or soldered to the distal end of the guide wire core.
The kinked, bent or curved tip in the guide wire and similar bend in the guide catheter enable the cardiologist to guide the tip of the catheter during catheter advancement, which involves pushing and rotating the bent tip within the patient's vascular system. To rotate and steer the guide wire, the cardiologist manually twists the external proximal portion of the catheter guide wire. The bent tip further allows the cardiologist to clearly discern the distal tip of the guide wire under fluoroscopy. Accordingly, such angled or bent guide wires have been found to be very helpful to negotiate tortuous blood vessels with angled branches and varying diameters.